1. Field of the Invention
This invention relates to isomeric 11-oxatricyclo[7. 3.0.0.sup.2,6 ]dodecene derivatives, to a process for their production and to their use as fragrances.
2. Statement of Related Art
Some 11-oxatricyclo[7.3.0.0.sup.2,6 ]dodecene derivatives are known from the literature. K. Bruns, U. Weber and M. Meiertoberens obtained Diels-Alder adducts by reaction of an isomer mixture of 2,2,4(2,4,4)-trimethyl-1-vinylcyclopent-1-ene with maleic or citraconic anhydride and itaconic and acetylene dicarboxylic acid dimethyl ester. After reduction and cyclization, the Diels-Alder adducts were converted into tricyclic ethers with a variety of woody odor notes (Parfumerie u. Kosmetik, 1986 (67) 714).
Although the ethers synthesized by Bruns et al. have good fragrance properties, there is still a need for compounds having characteristic odor profiles of different quality. Accordingly, a search was made for compounds which were to have characteristic new odor profiles coupled with good persistence, odor intensity and emanative power.
According to the invention, this problem has been solved by new 11-oxatricyclo[7.3.0.0.sup.2,6 ]dodecene derivatives obtained by:
a) reaction of isomerically pure trimethylvinyl cyclopentenes (i.e. either 2,2,4- or 2,4,4-trimethyl-1-vinylcyclopent-1-ene) with maleic acid, its anhydride or dialkyl ester PA1 b) reaction of isomerically pure trimethylvinyl cyclopentenes (i.e. either 2,2,4- or 2,4,4-trimethyl-1-vinylcyclopent-1-ene) or mixtures of these trimethylvinyl cyclopentenes with fumaric acid or its dialkyl esters
or by
to form the corresponding Diels-Alder adducts, reduction of these adducts to the corresponding diols and subsequent cyclization.